The present invention relates to apparatus for connecting an electrical supply voltage to an electrical load, and in particular, to a device for automatically delaying the connection of an electrical supply voltage to an electrical load when the supply voltage has been restored after an interruption. The apparatus of the present invention makes provision for eliminating the delay if the interruption is only momentary. I also call the apparatus of the present invention an "Automatic Cold Start Randomizer", since it allows for effectively randomizing the time of reconnection of various electrical loads to an electrical supply voltage after a power interruption.
A major problem for public utility power companies is the sudden in-rush of demand on its generators when a broken power line or other fault is repaired and the entire electrical load of all the affected customers is suddenly imposed on the utility through the repaired fault. Utility companies call this occurrence a "cold start".
It is, therefore, desirable to apply the load gradually after a fault is repaired by staggering the reconnection between groups of customers and the power line. This can be accomplished by delaying the reconnection of each customer or group of customers by a different amount of time. Thus, for example, 5% of the customers might be reconnected in 10 seconds, 5% more in 20 seconds, 5% more in 30 seconds, and so on until all customers have been connected after 200 seconds This may be called "randomizing" the load reconnection after a cold start. In the past, this has been done manually by throwing circuit breakers or switches connected to the affected loads. This may require the dispatch of workmen to various locations in order to throw the affected circuit breakers or switches, a time-consuming and expensive task.